The present invention relates to reflectors and, in particular, to reflectors for headlamps mounted on motor vehicles.
The present invention is primarily related to motor vehicles headlamps utilized to accommodate the aerodynamic styling of automobiles. With conventional approaches, each new aerodynamic or "aero" car model requires specifically designed headlamps; in particular a right and a left headlamp. Each "aero" car body style requires different slope or rake angles and a slightly different peripheral shape. As a result, each motor vehicle headlamp commonly has a lens specifically designed for the particular aero car model of concern. Because of the various different aero car models, various lenses specific to each model need to be provided.
If the light output of the motor vehicle headlamp was developed entirely by the reflector, the lens could be optically passive or neutral and need only be implemented for cosmetic and not optical purposes. Further, such a reflector could be designed so that one reflector could accommodate the optical requirements of a variety of automobile body styles with the lens and bezel systems filling in for slight size differences of mounting and the motor vehicle. Further, if the headlamps placed on the right and left sides of the vehicle could be designed so that a single reflector-source system produced the desired headlamp beam, then further needs of the lens could be eliminated. Such a reflector source system would have peripheral geometry designed so as to fit into proper relationship to the vehicle body and the cavity available in the fender compartments. The aerodynamic shape of the vehicle would be attained by suitably shaped and format lenses for the right and left sides of the vehicle. These lenses and their associated tooling would be much less expensive because there would be no need for the complex optics for lenses required to produce the necessary beam pattern on the roadway.
An additional advantage of eliminating the lens as it is related to the development of the light output of the headlamp, is that one source of light projection inaccuracy would be eliminated. In contemporary lamps having a reflector and lens combination, light source position, reflector accuracy and lens prescription, each disadvantageously contribute against obtaining the desired accuracy of the developed beam and often disadvantageously act in concert. In such an arrangement there are six possible error contributors. By eliminating the lens effect, three disadvantageous contributors are eliminated. More particularly, lens and reflector, lens and source, and lens-reflector-source interactions are obviated by elimination of lens optics.
U.S. Pat. No. 3,700,883 of Donahue and Joseph discloses a cornering lamp for a motor vehicle having an optically passive or neutral lens. This vehicle lamp, while serving its desired purpose as a cornering lamp, has optical parameters such as spherical, parabolic, and right cylindrical surfaces. Cornering lamps employing cylindrical surfaces, by their very nature diffuse the compactness of light projected off of their surfaces. While this is desirable in producing the wide beam desired of a stop/tail lamp related to a cornering lamp, it is contrary to the interest and needs of headlamp beams which are very compact and specific in their light distribution. It is desired that a motor vehicle headlamp develop a compact light distribution and have an optically passive lens so that it may be utilized to serve the needs of the aerodynamic styling of automobiles.
Accordingly, an object of the present invention is to provide a motor vehicle headlamp wherein the optics required to provide the desired illumination of the vehicle are placed entirely on the reflector so as to project a beam outward in a desired compact illumination pattern to serve the highway need of a motor vehicle.
Another object of the present invention is to provide the reflector comprising faceted surfaces which provide a projected beam of predetermined intensity distribution.
Another object of the present invention is to provide the headlamp unit wherein glare is sufficiently reduced by providing selective orientation of the facets of the reflector.